This is what I get when it's running good. I'm using Windows's driver, but have the same issue with Samsung's.
when the performance drops. I don't have any screenshots of those, but everything drops...

I found a great deal on (4) 860 EVO 1TB SATA III drives on Black Friday, but they're plugged into the SATA III ports 1-4 (PCH) and shouldn't
really affect the m.2 ports. The 970 pro is running great...